I worked my way backward to this conclusion. When thinking about people I consider poor decision-makers, I realized that their true deficiency was identifying options. These are the people that will often lament after the fact – if I’d known about THAT, I would have done it differently! It's a suggestive complaint, implying that if we are given the right choices, we always make the right decisions.
There are some who are surely scratching their heads at this point. What’s the point of this, aren’t these the same thing, isn’t choosing an option always just a decision, the decision being which option? Perhaps my, eh hem, ‘insight’ is all semantics, so I’ll concede the point, but let's try it another way – the skill of ‘decision-making’ masks the more relevant skill of ‘defining options’.
People who thoroughly identify their options seem to take advantage of an almost-innate human capacity for selection. So, my advice to someone who wants to make better decisions is that instead of weighing the merits of A or B, learn to identify additional options, C, D, and E, because the more good options we have, the more likely we are to make the right decision.